autolinking libraries

I'm trying to create a set of C++ libraries, but I want to be able to just include the header file without setting the project to link to the .lib file. This can be accomplished by including the line:

#pragma comment( lib, "lib_path" )

However, to be able to do this I need to be able to detect which version of the CRT the including program is linked to (release, debug , multithreaded etc), so I can link the appropriate version of my library. Does anybody know how to do this? P.S. I intend to wrap all this in an #if _MSC_VER, so that the library headers are still compatible with other compilers.